Consumers have been treating amino acid based substrates for years. Such treatments have included the waterproofing or coloring of textiles, the sunscreening of skin, the coloring, conditioning, and styling of hair, the dentifrice treatment of teeth, and more. It is well known that if such treatments can be done by safe covalent attachment to the substrate, that the treatment will be much more long lasting. Therefore, several reactive chemistries have been developed to provide covalent attachment to amino acid based substrates such as hair. Historically, these technologies, based on covalent attachment of cosmetic actives, have primarily relied upon electrophilic (electron accepting) and nucleophilic (electron donating) reactive groups or “hooks”. (Please see WO98/38974 by G. Malle et. al., U.S. Pat. No. 5,935,560 by J. Seper et. al., U.S. Pat. No. 5,525,332 by A. Gough et. al., WO96/03966 by P. Baile et. al., U.S. Pat. No. 5,523,080 by A. Gough et. al., WO94/26237 by A. Gough et. al., U.S. Pat. No. 5350572 by A. Savaides et. al., U.S. Pat. No. 5,254,335 by T. Deppert et. al., U.S. Pat. No. 5,206,013 by T. Deppert et. al., U.S. Pat. No. 5,211,942 by T. Deppert et. al., EP0 437099A1 by D. Halloran et. al., CA 2024509AA by B. Murphy et. al., U.S. Pat. No. 5,087,733 by T. Deppert et. al., U.S. Pat. No. 5,030,756 by T. Deppert et. al., U.S. Pat. No. 4,973,475 by R. Schnetzinger et. al., GB 2197887A by C. Mahieu et. al., U.S. Pat. No. 4,567,039 by R. Stadnick et. al., EP0 159628 by R. Stadnick et. al., U.S. Pat. No. 4,102,641 by A. Cunningham et. al., U.S. Pat. No. 3,549,602 by G. Kalopissis et. al., U.S. Pat. No. 3,484,417 by G. Kalopissis et. al.) More recently, a Protected Thiols “hook” technology for the covalent attachment of cosmetic actives to amino acid substrates has been proposed. (Please reference WO2000040210A2 by R. Glenn et. al., and WO2000040209A2 by R. Glenn.)
It is highly desirable to formulate and apply hair care products as aqueous solutions or aqueous emulsions for a number of consumer preferred attributes. Aqueous solutions provide superior ease of rinsing, hair feel, less coating of bathroom tiles, etc. than oil based compositions. However, attaining such aqueous compositions is problematic. The reactive groups or “hook” moieties which are reactive towards amino acid residues, are also reactive towards electron rich ingredients that are employed in the formulation of consumer products to deliver these actives, including water and even atmospheric oxygen. This leads to pre-mature decomposition of the “hooks” compounds, referred to herein as reactive agents, over the shelf life of the product which severely or completely mitigates reactive efficacy with hair upon usage by the consumer.
The primary advantage of this invention is the discovery of a delivery system approach that will enable the treatment of reactive agents to hair from a 1) chemically shelf stable composition that is 2) applied to hair in a consumer desired product form, e.g., as an aqueous emulsion.
This is accomplished via a self-emulsifying hair delivery system comprising a separately packaged liquid emulsifiable concentrate that is essentially non-aqueous, comprising the reactive agent, that is able to self or spontaneously emulsify upon dilution with water or a separate aqueous composition. Such dilution may be done by the consumer, to form an aqueous micro- or macro-emulsion with minimal or no agitation either immediately prior to or simultaneous to application to hair. While not being bound by theory, such low energy emulsification with minimal or no agitation by the consumer, e.g., by soft shaking of bottle or suitable container, is achieved via inclusion of specialized surfactants and/or dispersing aides within the liquid concentrate that achieve either ultra-low interfacial tension and/or substantial interfacial disruption between the liquid concentrate and the aqueous phase upon dilution with water or a separately packaged aqueous composition.
Surprisingly, it has been discovered that the liquid emulsifiable concentrates of the present invention can achieve self emulsification even upon addition to a substantially thickened aqueous composition to produce a resulting homogenous and viscous emulsion with minimal agitation by the consumer, e.g., via gentle shaking of the bottle or suitable container container. This is in marked contrast to conventional thickened emulsions which necessitate considerable energy input that can only be attained by employing high energy processing equipment within a laboratory or a manufacturing plant, e.g., a lightning mixer or agitated vessel. Accordingly, the liquid emulsifiable concentrates of the present invention enable isolation upon storage for acceptable chemical shelf stability while still enabling emulsion delivery with minimal inconvenience to the consumer.